Internal lock



FIG. 1 is a perspective view of an internal lock showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a front perspective view thereof, shown in an expandedposition.

The ornamental design for internal lock, as shown and described.